54 



POPULAR SOIEI^CE NEWS. 



[Ai'uii., 1889. 



that is, free from all suspended matter, such as clay, 

 mud, fragments of leaves, sedimentary matter, etc. 

 Even though such matter be not in itself poisonous, 

 or even to any extent appreciably detrimental to 

 health, it will still be offensive to the eye, and the 

 presence of such impurities will detract from the en- 

 joyment attendant on its use. So also in the bath, 

 the water should appear pellucid and inviting, and 

 any matter which in any way prevents it from being 

 so is offensive. 



The water should contain a sutTiciency of dissolved 

 gases, especially oxygen gas. A water not contain- 

 ing sufficient dissolved gases will taste flat, and thus 

 be offensive to the sense of taste. 



The water should be free from any marked taste, 

 other than the agreeable sensation imparted by a 

 pure and sparkling water. Any taste that a water 

 may possess will offend the sense of taste, and will 

 render the water unpalatable to many people. 



The water should be free from any color, which, 

 although such coloration may in certain cases be 

 not deemed detrimental to health, is most certainly 

 offensive to the eye, and will excite a feeling of re- 

 pulsion, rather than of agreeable expectation. Such 

 a coloration also causes in the minds of many per- 

 sons, especially among the uneducated, feelings of 

 alarm as to the safety of the water. 



The water should be free from any odor, since the 

 presence of a recognizable odor offends the sense of 

 smell, as well as at once awakens feelings of alarm 

 among the people. Nor should it, on standing, 

 develop any unpleasant odor, since it will then also 

 become offensive. 



The water should be as free as possible from min- 

 eral matter, since its presence in any considerable 

 amount may cause the water to produce certain 

 specific physiological effects, and thus render it 

 offensive to the public health. Organic matter, in 

 any amount, should also be absent, since it may. 

 aside from exerting any physiological effects, afford 

 nutriment and means of development for numerous 

 species of lower organisms, both vegetable and ani- 

 mal, many of which, such, for instance, as the 

 pathological bacteria or disease-germs, may cause 

 the water to become the means of spreading disease, 

 and thus endanger the public health and increase the 

 death rate. 



Any substance which, when added to a drinking 

 water, causes the water to offend the senses of sight, 

 smell or taste, or which makes the water unhealthv 

 or dangerous to drink, is offensive matter, and will 

 render the water less pure, or impure. 



In relation to the uses of water for household pur- 

 poses, the addition to the water intended for these 

 purposes, washing, the preparation of food, etc., 

 which in any way is detrimental to its adaptability 

 to these uses, is offensive matter, and will make the 

 water impure. Not alone will it render the water 

 impure, but it may, in case the hardness is increased, 

 cause an increase in the expenses of housekeeping, 

 as, for instance, in the increased use of soap, which 

 will be brought about by an increase in the hard- 

 ness. 



Again, the addition of any matter which may 

 increase the hardness of the water, or which may 

 Increase the amount of total dissolved solids, will 

 cause the water to form scales in boilers more 

 rapidly, and thus not only compel a greater use of 

 fuel by those who use steam, but will also shorten 

 the lives of the boilers, thus adding to the cost of 

 steam-making, and will also increase the dangers 

 attendant on their use. Any substance which, 

 when added to a water, will render it less adapted 

 for use in steam boilers, is an oftensive substance. 



Further, any substance which, when added to 

 a water, renders it less adapted for use in the house- 

 hold or in manufacturing, will increase 'the cost »( 



living or manufacturing in the cases of some or 

 many of the inhabitants of the city, and thus to a 

 lesser or greater extent will eventually injure the 

 prosperity of the town by decreasing the amount of 

 capital available for enterprise or investment. Any 

 matter in any way causing or bringing about these 

 results, we may consider offensive. 



It is also to be noted as a fact that must not be 

 overlooked, that the water of a city-supply is 

 judged by certain forms of chemical analysis. It is, 

 hence, evident that any matter which, when present 

 in the water-supply, is condemned by the analysis, 

 must also be condemned if found present in the 

 water entering the supply, and that wastes, etc., 

 containing constituents which will cause the water- 

 supply to be adjudged impure, must be condenmed 

 as offensive. 



The question may arise as to how to deal with 

 waste waters discharged into a water-supply, which, 

 while iiot so pure as the supply, are still not so im- 

 pure in any individual case as to excite apprehension. 

 If only one such case occurred, no great danger 

 might be feared, but when a number of such waters 

 enter the river, the effect of them all will become 

 very appreciable. In this case, strict impartiality is 

 the only safe-guard, and the total evil should be 

 abolished by abolishing each and every cause of it. 

 No matter of anj' kind should be allowed to enter a 

 water-supply, which in any way renders the water 

 less adapted for potable, household, and manufac- 

 turing purposes by the users thereof 



Rutgers College, New Brlnswick, N. J. 



THE CHEMICAL NATURE OF ASSIMILA- 

 TION. 

 BoKORNY has conducted some interesting experi- 

 ments designed to test the truth of the hypothesis of 

 Baeyer, namel}', that when sunlight acts on chloro- 

 phyll which is surrounded by carbon-dioxide, the 

 gas undergoes dissociation, as if it were exposed to 

 a high temperature, andoxygen is eliminated. Fur- 

 ther, from this dissociation, carbon monoxide re- 

 sults, and is united to the chlorophyll, where it at 

 once takes up a molecule of water, forming formic 

 aldehyd. In the presence of the free alkalies of the 

 assimilating cells, this primary product can pass at 

 once into the form of sugar. Bokorny has contrived 

 to exclude carbonic acid from the assimilating cells 

 of Sjiiroffi/ra, providing, in place of this gas, formic 

 aldehyde, methylaldehyde, methyl-alcohol, and, as 

 others had done before him, glycerin. He found 

 that formic aldehyde killed the protoplasm, but he 

 does not regard this as vitiating the hypothesis of 

 Baeyer, since it is possible that this substance is, in 

 normal assimilation, converted at once into a carbo- 

 hydrate. With the other substances employed he 

 was moderately successful, and states that from 

 them, even with complete exclusion of carbonic 



acid, the green cells of a plant can produce starch. 

 _<♦( 



THE INCINERATION OF ORGANIC MATTER. 



In order to incinerate substances which, during 

 incineration, swell up strongly like sugar, or defla- 

 gate slightly, or give off dust like the salts of the 

 organic nitro-acids, Kronberg weighs off a portion 

 of the pulverized sample in a glass tube which can 

 be stoppered, and transfers it to the platinum cruci- 

 ble in such small portions that no tumefaction or 

 dispersion of ashes can take place. The crucible 

 contains, as a stirring-rod, a short, thick, straight, 

 platinum wire, which projects above the edge of the 

 crucible only so far that it may be grasped, passes 

 through n very small lateral opening in the edge 

 of the lid, and is weighed along with the crucible and 

 lid. The charge is ignited, the crucible being cov- 

 ered, beginning at the side, and continuing to ignite 

 with the crucible placed in a slantingposition. The 



ash is crushed, if necessary, with the platinum rod, 

 the crucible is iet cool, and a further portion of the 

 substance is added and treated as above. When a 

 sufficient quantity of the ash has thus collected, the 

 entire mass is ignited at a higher temperature. For 

 the completion of the incineration, if nitric or sul- 

 phuric acid is inadmissible, the crucible is let cool 

 down to about the boiling-point of water, and so 

 much water is added, drop by drop, along the side 

 of the crucible that on stirring with the wire all the 

 soluble salts are dissolved. Any carbonaceous mat- 

 ter remaining is brought to the sides of the crucible, 

 the small quantity of water is cautiously evaporated 

 away, and the whole is re-ignited. — Chemiker 

 Zeitung. 



A DOUBLE-POINTED NAIL. 

 A NEW and convenient form of nail is here repre- 

 sented, which is very useful for fastening pieces of 

 wood together, where an invisible joint is 

 desired which will not mar the surface. 

 The nail is driven into the first piece of 

 wood in the ordinary way, by striking upon 

 the face, A. After it has been driven down 

 to B, the second piece of wood is placed 

 upon the upper point, and hammered down 

 until it is in contact with the first one. A 

 close and firm joint is thus produced, in 

 which no nail-holes can be seen. This 

 tbrm of nail is especially useful for furni- 

 ture and cabinet work, but, if desired, they 

 can be made of a size suflicient to fasten the strong- 

 est and heaviest timbers together. 



LABORATORY NOTES. 



Removal of Fused Masses from 1'latinum 

 Crucibles. — As soon as the fusion is completed, the 

 coiled end of a platinum wire is put into the nuiss, 

 which is then allowed to cool. The wire is about 

 10 cm. long, and ends in a loop, so that it may be 

 suspended from a hook. When suspended, the cru- 

 cible is brought at about half an inch distance from 

 a pipeclay triangle, and then suddenly heated. In a 

 few seconds the crucible will detach itself and drop 

 into the triangle, whilst its contents stick to the 

 wire. The small quantity of salts still adhering to 

 the crucible may, of coiwse, be removed by suitable 

 means. The wire i.s now made to slip into a beaker 

 filled with water or acid, when, owing to the salts 

 being on the top of the tiuid, solution takes place 

 with great rapidity. 



A New Test for Copper Salts. ^This is very 

 simple, and extremely delicate ; hence it will be 

 found of great use in testing various ores, articles of 

 food and drink, and pharmaceutical preparations 

 suspected of containing minute quantities of copper. 

 The only precaution needful is to see that the fluid 

 to be examined is either neutral, or, at least, not 

 strongly alkaline. A faintly acid reaction does not 

 vitiate the result. The test re-agent is prepared by 

 dissolving in (say) one and a half fluid ounces of 

 neutral sulphite of sodium — three parts of a saturated 

 solution mixed with one part of distilled water — 

 about three drachms of pyrogallol, subsequently 

 adding another half-ounce of the sulphite .solution, 

 and filtering the mixture. A few drops of this re- 

 agent gives a deep orange-red coloration in clear, 

 dilute solutions of copper. If the latter metal be 

 present in quantity represented by only one part of 

 the sulphite of copper in three or four million parts 

 of water, the reaction afforded is still quite distinct 

 and characteristic. 



<♦> 



TiiK total number of bodies cremated in the 

 various countries to the 1st of August, is as fol- 

 lows: Italy, 998; Gotha. 554; America, JS7; Swe- 

 den, 39; England, 16; Fiance, 7; Denmark, i. 



